Atrial compliance changes in animal total artificial heart recipients.

Right atrial compliance of chronically implanted total artificial heart animals was calculated from the pressure-volume relationships acquired at autopsy and compared with those of a control animal. The chronically implanted animals showed right atrial dilatation and low compliance. Even though atrial dilatation and decreased compliance have an opposite direct effect on atrial pressures, these changes may, in turn, disturb stretch-dependent volume regulatory processes, resulting in high atrial pressure.